SlvrP5

Only a joke! ....I've never put 91 in anything i've owned. I'm too cheap

KrayzieFox

It's pointless anyway .. unless the car specifically asks for it.

silverpro5

Would it be pointless to use midgrade? Whenever I fill it up with the cheap stuff I feel like I'm cheating my engine out of sweet octane goodness.

aMaff

The car's tuned to run on 87. Anything more is pretty much useless.

JoshP5

Some people (like me) get a little bit of detonation using 87, so I use 89. Problem solved. In this sense it's not pointless to use 89.

PS I also get 1 or 2 mpg better on 89.

aMaff

Fair enough, but you *shouldn't* be getting detonation. if you are, there's probably a bigger problem.

KrayzieFox

Our 89 is a 10% Ethanol blend so it's probably worse than 87 would be. But since I've been using 87 ever since I bought the car and have had absolutely no problems with it, I really don't care about anything above that.

JoshP5

Such as?

This is my second Mazda that did this, never had any other "problems" with either one.

aMaff

No idea. I'm no engine expert by any means, however I know that on an engine tuned to run on 87, if you're getting detonation something's up. Factory defect / funk / statistic maybe? Has it done it from day one? Bad gas maybe?

JoshP5

I figured it was due to slightly high intake charge temp or something like that. I lived in Tucson for 5 years with the Miata, and only noticed the P5 doing it this summer. I can hear it when lugging the engine with the windows down driving next to walls, otherwise it's imperceptible.

aMaff

I'm in Georgia...it's hot here too. I never had a problem w/ pinging. Of course, I run 93 now that I have the MP3 brain in there...

Jackelope

changed my radiator cap over weekend, changed t-stat about an hour ago - hopefully that fixes de overheating problem

Liquid_Ag

mmm mp3 brain

aMaff

so long as you're moving... and don't have the a/c on LOL

Liquid_Ag

indeed. omg wtf?